At which layer does the application-aware firewall block applications on a WAN Edge?

Layer 3 (Network layer) firewalls block based on IP addresses and protocols, not specific applications.

Layer 5 (Session layer) firewalls focus on session establishment and termination, not deep application content inspection.

Layer 2 (Data Link layer) security typically involves MAC addresses and VLANs, not application blocking.

An application-aware firewall functions at Layer 7 (the Application layer) of the OSI model. By operating at this layer, it can inspect the actual application traffic and protocols (e.g., HTTP, FTP, DNS) to identify and block specific applications or application functions, providing granular control beyond traditional port-based filtering.